Silicones have been used extensively for fiber or textile treatments. In particular, various amine functional silicones have been developed and sold commercially under various tradenames. Common problems associated with amine functional silicones as textile treatments are their yellowing of textiles from the oxidation of the amine groups and extensive hydrophobic nature of the polydimethylsiloxane chains. Thus, efforts over the years have focused on modifying amine functional silicones by adding hydrophilic groups to the siloxane polymers, while altering or reducing the amine content to reduce yellowing. For example, JP09183854, and JP03269570 describe a copolymer prepared by first making a block copolymer from Si—H terminal polydimethylsiloxane and allyl or methallyl terminal polyether, and then equilibrating that copolymer with an aminosiloxane to incorporate the amine functionality.
There are several shortcomings using an equilibration method to incorporate amine functionality into a silicone polyether copolymers. For example, ensuring complete equilibration (randomization of the amine groups) can take a long time, and it is difficult to assess if the amine becomes sufficiently randomized in the copolymer. Furthermore, at low amine concentrations, a significant portion of the polymer chains will have no amine functionality.
The present inventors have discovered certain silicone polyether block copolymers that eliminate some of these disadvantages. The silicone polyether block copolymers may be prepared by hydrosilylating an SiH terminal silicone polyether block copolymer with an epoxy functional olefin such as allyl glycidyl ether or vinyl cyclohexene oxide. Then, the epoxy groups are reacted with an amine to convert the epoxides into beta hydroxy amine groups. Alternately, the epoxy groups may be reacted with tertiary amine salts to convert the epoxides into beta hydroxy quaternary ammonium groups. The advantage of using the hydrosilylation chemistry in conjunction with the amine-epoxide chemistry is that most polymer chains will contain hydrophilic polyether blocks and two amine groups. Furthermore, since the amine groups are at the chain end, it is possible to use a minimal amount of amine to minimize yellowing of fabrics. The amine groups can be further converted to the salt form by addition of acid or converted to their quaternary ammonium forms via the use of common quaternizing agents such as alkyl halides, benzyl halides, alkyl sulfates, aryl sulfates, or chloroacetate esters.